title: A critical role for CHIP in the aggresome pathway.
abstract: Recent evidence suggests that aggresome formation is a physiologic stress response not limited to misfolded proteins. That stress response, termed "physiologic aggresome," is exemplified by aggresome formation of inducible nitric oxide synthase (iNOS), an important host defense protein. CHIP (carboxy terminus of Hsp70-interacting protein) is a highly conserved protein that has been shown to mediate substrate ubiquitination and degradation by the proteasome. In this study, we show that CHIP has a previously unexpected critical role in the aggresome pathway. CHIP interacts with iNOS and promotes its ubiquitination and degradation by the proteasome as well as its sequestration to the aggresome. CHIP-mediated iNOS targeting to the proteasome sequentially precedes CHIP-mediated iNOS sequestration to the aggresome. CHIP is required for iNOS preaggresome structures to form a mature aggresome. Furthermore, CHIP is required for targeting the mutant form of cystic fibrosis transconductance regulator (CFTRDeltaF508) to the aggresome. Importantly, the ubiquitin ligase function of CHIP is required in targeting preaggresomal structures to the aggresome by promoting an iNOS interaction with histone deacetylase 6, which serves as an adaptor between ubiquitinated proteins and the dynein motor. This study reveals a critical role for CHIP in the aggresome pathway.
authors.affiliation: Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Youbao
authors.initials: Y
authors.lastname: Sha
authors.forename: Lavannya
authors.initials: L
authors.lastname: Pandit
authors.forename: Shenyan
authors.initials: S
authors.lastname: Zeng
authors.forename: N Tony
authors.initials: NT
authors.lastname: Eissa
mesh_terms: D002460:Cell Line; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism; D003600:Cytosol / Q000187:drug effects / Q000201:enzymology; D003902:Detergents / Q000494:pharmacology; D004398:Dyneins / Q000378:metabolism; D055785:Gene Knockdown Techniques; D000073864:Histone Deacetylase 6; D006655:Histone Deacetylases / Q000378:metabolism; D006801:Humans; D002479:Inclusion Bodies / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D010641:Phenotype; D046988:Proteasome Endopeptidase Complex / Q000187:drug effects / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000187:drug effects; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry / Q000378:metabolism*; D054875:Ubiquitination / Q000187:drug effects
chemical_list: D003902:Detergents; C093349:cystic fibrosis transmembrane conductance regulator delta F508; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D052247:Nitric Oxide Synthase Type II; C467728:STUB1 protein, human; D044767:Ubiquitin-Protein Ligases; D046988:Proteasome Endopeptidase Complex; C433811:HDAC6 protein, human; D000073864:Histone Deacetylase 6; D006655:Histone Deacetylases; D004398:Dyneins